Bags of various sizes are known in the art which, for the most part, are of a predetermined fixed size. However, it is desirable in many instances to have a bag which can be used either in a larger size or in a smaller size. If one is to shop or pack only a limited number and/or amounts of goods, it is more convenient to have a bag of smaller size. By contrast, if the bag is to hold a large amount of items, a bag of larger size is desirable which can be readily changed back to the smaller size as the need arises.
An expandable bag is particularly useful with a so-called "LOAD LLAMA".TM. bicycle rack mounted over the rear wheel of a bicycle which has an adjustable support area for goods to be carried on the bicycle rack. The so-called "LOAD LLAMA".TM. bicycle rack, which is commercially available, incorporates the adjusting features of U.S. Pat. Nos. 5,217,149 and 5,222,639 as well as additional features described in U.S. Pat. No. 5,655,676. As disclosed in the aforementioned U.S. Pat. No. 5,655,676, the rotatable and axially extendable L-shaped support arms can be axially adjusted between an axially fully retracted position providing a minimum width support area position on the rack and an axially maximum extended position providing a maximum width support area position on the rack by limiting the maximum extension of the support arms in the axial direction thereof.